發(fā)布時(shí)間：2018-04-14 11:25

  本文選題：牛磺酸 + 雌二醇��； 參考：《中國(guó)農(nóng)業(yè)大學(xué)》2015年博士論文

【摘要】：半胱亞磺酸脫羧酶(CSAD)和半胱氨酸雙加氧酶(CDO)是�；撬岷铣傻南匏倜�,它們?cè)诟闻K生理和病理過(guò)程中發(fā)揮諸多作用,并且其表達(dá)水平與體內(nèi)的性激素含量有一定關(guān)聯(lián)。然而�；撬岷铣擅概c性激素在小鼠肝臟中的具體調(diào)控關(guān)系尚不明確。本研究的目的是在小鼠肝臟和肝實(shí)質(zhì)細(xì)胞中探索雌二醇和睪酮如何調(diào)控�；撬岬暮�量及其合成酶的表達(dá)。 我們初步觀察到：相對(duì)于發(fā)情間期,雌性小鼠在發(fā)情期CSAD、CDO和�；撬岬乃�平較低。隨后用不同劑量雌二醇來(lái)處理摘除卵巢后的小鼠,肝實(shí)質(zhì)細(xì)胞和HepG2細(xì)胞系,并分析CSAD和CDO的表達(dá)以及�；撬岬暮�量。結(jié)果顯示雌二醇可以降低血清中和肝臟中牛磺酸的含量,并且這種作用主要是通過(guò)抑制CSAD和CDO的表達(dá)水平來(lái)實(shí)現(xiàn)的。之后我們進(jìn)一步確定了介導(dǎo)雌二醇發(fā)揮該作用的受體類型。實(shí)驗(yàn)結(jié)果顯示在肝臟和肝實(shí)質(zhì)細(xì)胞中雌激素受體α (ERα)的表達(dá)要高于雌激素受體β (ERβ)。在雌激素受體抑制劑ICI182,780提前處理肝臟和肝實(shí)質(zhì)細(xì)胞中,雌二醇對(duì)二者CSAD、CDO和�；撬崴�平的抑制程度有所解除。在雌激素受體敲除小鼠實(shí)驗(yàn)中發(fā)現(xiàn),外源和內(nèi)源的雌二醇都不能在ERa敲除小鼠中抑制�；撬岷铣擅傅谋磉_(dá)水平和降低血清中與肝臟中�；撬岬暮�量。 在雄鼠中,肝內(nèi)�；撬峒捌浜铣擅窩SAD與CDO的表達(dá)水平會(huì)被睪丸摘除顯著地降低,然而外源雄激素注射后會(huì)明顯地回補(bǔ)其到正常水平。在肝實(shí)質(zhì)細(xì)胞和HepG2細(xì)胞系中也有觀察到睪酮對(duì)胞內(nèi)CSAD表達(dá)水平的促進(jìn)。隨后我們發(fā)現(xiàn),氟他胺的提前處理可以部分地解除睪酮對(duì)牛磺酸含量及其�；撬岷铣擅副磉_(dá)的促進(jìn)作用。熒光素酶實(shí)驗(yàn)也證明了睪酮發(fā)揮對(duì)CSAD的促進(jìn)作用依賴于雄激素受體。此外我們還發(fā)現(xiàn)了睪酮對(duì)CDO的調(diào)控主要體現(xiàn)在對(duì)CDO蛋白質(zhì)水平的調(diào)控而非在mRNA表達(dá)層面。 此外,我們的實(shí)驗(yàn)結(jié)果還發(fā)現(xiàn)了CSAD以及CDO的表達(dá)與HepG2細(xì)胞系和293FT細(xì)胞系中活性氧含量間存在正相關(guān),然而這種相關(guān)性與胞內(nèi)谷胱甘肽的含量沒(méi)有直接關(guān)聯(lián)。具體的機(jī)制還有待進(jìn)一步深入的研究。 綜上所述,我們的實(shí)驗(yàn)結(jié)果表明,性激素可以在小鼠肝內(nèi)和肝細(xì)胞內(nèi)調(diào)控�；撬岬暮�量以及牛磺酸合成酶的表達(dá),并且這種作用有核受體依賴性。此外�；撬岷铣擅傅谋磉_(dá)水平也與胞內(nèi)的活性氧水平有關(guān)。
[Abstract]:Cysteinesulfonic acid decarboxylase (CSAD) and cysteine dioxygenase (CDO) are rate-limiting enzymes for taurine synthesis. They play many roles in the physiological and pathological processes of the liver, and their expression level is related to the content of sex hormones in vivo.However, the specific regulatory relationship between taurine synthase and sex hormone in mouse liver is unclear.The aim of this study was to explore how estradiol and testosterone regulate taurine content and the expression of synthase in liver and parenchyma cells of mice.We preliminarily observed that the levels of CSAD CDO and taurine were lower in female mice than in estrus.After ovariectomized mice liver parenchyma cells and HepG2 cell lines were treated with different doses of estradiol. The expression of CSAD and CDO and the content of taurine were analyzed.The results showed that estradiol could decrease the content of taurine in serum and liver, and this effect was mainly achieved by inhibiting the expression of CSAD and CDO.We then further identified the type of receptor that mediates the role of estradiol.The results showed that the expression of estrogen receptor 偽 (ER 偽) in liver and hepatic parenchyma cells was higher than that in estrogen receptor 尾 (ER 尾).The inhibition of estradiol on CDO and taurine levels in liver and hepatic parenchyma cells was relieved by estrogen receptor inhibitor ICI182780.In estrogen receptor knockout mice, it was found that both exogenous and endogenous estradiol could not inhibit the expression of taurine synthase in ERa knockout mice and decrease the content of taurine in serum and liver.In male rats, the expression of taurine and its synthase CSAD and CDO in the liver was significantly decreased by testicular excision, but it was significantly restored to normal level after injection of exogenous androgen.The effect of testosterone on intracellular CSAD expression was also observed in hepatic parenchymal cells and HepG2 cell lines.After that, we found that the advance treatment of flutamide could partially remove the effect of testosterone on taurine content and taurine synthase expression.Luciferase assay also demonstrated that testosterone plays a role in promoting CSAD dependent on androgen receptors.In addition, we also found that the regulation of testosterone on CDO is mainly reflected in the regulation of CDO protein level rather than in the level of mRNA expression.In addition, we also found that there was a positive correlation between the expression of CSAD and CDO and the content of reactive oxygen species in HepG2 and 293FT cell lines, but there was no direct correlation between the expression of CSAD and CDO and the content of intracellular glutathione.The specific mechanism remains to be further studied.In conclusion, our results suggest that sex hormones can regulate taurine content and taurine synthase expression in the liver and hepatocytes of mice, and this effect is nuclear receptor-dependent.In addition, the expression level of taurine synthase is also related to the level of reactive oxygen species.
【學(xué)位授予單位】：中國(guó)農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：S865.13

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本文編號(hào)：1749110